IT1111425B - Trasduttore assoluto di precisione per misure di posizioni lineari od angolari - Google Patents

Trasduttore assoluto di precisione per misure di posizioni lineari od angolari

Info

Publication number
IT1111425B
IT1111425B IT68123/77A IT6812377A IT1111425B IT 1111425 B IT1111425 B IT 1111425B IT 68123/77 A IT68123/77 A IT 68123/77A IT 6812377 A IT6812377 A IT 6812377A IT 1111425 B IT1111425 B IT 1111425B
Authority
IT
Italy
Prior art keywords
linear
measurement
angular positions
absolute precision
precision transducer
Prior art date
Application number
IT68123/77A
Other languages
English (en)
Italian (it)
Original Assignee
Conte Alberto
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Conte Alberto filed Critical Conte Alberto
Priority to IT68123/77A priority Critical patent/IT1111425B/it
Priority to DE19782817544 priority patent/DE2817544A1/de
Priority to GB16329/78A priority patent/GB1595127A/en
Priority to CA000302189A priority patent/CA1136238A/en
Priority to SE7805231A priority patent/SE426989B/sv
Priority to FR7813644A priority patent/FR2391451A1/fr
Priority to MX173437A priority patent/MX149962A/es
Priority to AU36069/78A priority patent/AU524646B2/en
Priority to NO781717A priority patent/NO151172C/no
Priority to JP5771378A priority patent/JPS53143348A/ja
Priority to NLAANVRAGE7805353,A priority patent/NL188541C/xx
Priority to CH535778A priority patent/CH623412A5/it
Priority to BR787803124A priority patent/BR7803124A/pt
Priority to SU782619552A priority patent/SU759059A3/ru
Priority to US06/125,432 priority patent/US4504832A/en
Application granted granted Critical
Publication of IT1111425B publication Critical patent/IT1111425B/it

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/25—Selecting one or more conductors or channels from a plurality of conductors or channels, e.g. by closing contacts
    • G01D5/252—Selecting one or more conductors or channels from a plurality of conductors or channels, e.g. by closing contacts a combination of conductors or channels
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
    • G01D5/204—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils
    • G01D5/2073—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils by movement of a single coil with respect to two or more coils
    • G01D5/208—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils by movement of a single coil with respect to two or more coils using polyphase currents
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/24—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
    • G01D5/241—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes
    • G01D5/2412—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes by varying overlap
    • G01D5/2415—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes by varying overlap adapted for encoders
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H03M1/22—Analogue/digital converters pattern-reading type
    • H03M1/24—Analogue/digital converters pattern-reading type using relatively movable reader and disc or strip
    • H03M1/26—Analogue/digital converters pattern-reading type using relatively movable reader and disc or strip with weighted coding, i.e. the weight given to a digit depends on the position of the digit within the block or code word, e.g. there is a given radix and the weights are powers of this radix

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
IT68123/77A 1977-05-18 1977-05-18 Trasduttore assoluto di precisione per misure di posizioni lineari od angolari IT1111425B (it)

Priority Applications (15)

Application Number Priority Date Filing Date Title
IT68123/77A IT1111425B (it) 1977-05-18 1977-05-18 Trasduttore assoluto di precisione per misure di posizioni lineari od angolari
DE19782817544 DE2817544A1 (de) 1977-05-18 1978-04-21 Absoluter genauigkeitstransduktor zum messen von linien- oder winkelstellungen
GB16329/78A GB1595127A (en) 1977-05-18 1978-04-25 Transducer for angular and linear measurement
CA000302189A CA1136238A (en) 1977-05-18 1978-04-27 Absolute precision transducer for linear or angular position measurements
SE7805231A SE426989B (sv) 1977-05-18 1978-05-08 Absolutlegestransor for linjera metningar och vinkelmetningar
FR7813644A FR2391451A1 (fr) 1977-05-18 1978-05-09 Transducteur de position absolue pour mesure de deplacement lineaire et
MX173437A MX149962A (es) 1977-05-18 1978-05-11 Mejoras en transductor de alta precision para medidas de posicion lineal o angular
AU36069/78A AU524646B2 (en) 1977-05-18 1978-05-12 Absolute precision transducer for linear or angular position measurements
NO781717A NO151172C (no) 1977-05-18 1978-05-16 Omformer for absolutt posisjon ved lineaer- og vinkelmaaling
JP5771378A JPS53143348A (en) 1977-05-18 1978-05-17 Absolute precise transducer for measurement of linear or angular location
NLAANVRAGE7805353,A NL188541C (nl) 1977-05-18 1978-05-17 Absolute positietransducent voor het meten van een lineaire en hoekpositie.
CH535778A CH623412A5 (en) 1977-05-18 1978-05-17 Absolute electrical precision transducer for measuring linear or angular positions
BR787803124A BR7803124A (pt) 1977-05-18 1978-05-17 Transdutor absoluto de precisao para medidas lineares ou angulares
SU782619552A SU759059A3 (ru) 1977-05-18 1978-05-18 Преобразователь перемещени в код
US06/125,432 US4504832A (en) 1977-05-18 1980-02-28 Absolute precision transducer for linear or angular position measurements

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT68123/77A IT1111425B (it) 1977-05-18 1977-05-18 Trasduttore assoluto di precisione per misure di posizioni lineari od angolari

Publications (1)

Publication Number Publication Date
IT1111425B true IT1111425B (it) 1986-01-13

Family

ID=11307996

Family Applications (1)

Application Number Title Priority Date Filing Date
IT68123/77A IT1111425B (it) 1977-05-18 1977-05-18 Trasduttore assoluto di precisione per misure di posizioni lineari od angolari

Country Status (15)

Country Link
US (1) US4504832A (sv)
JP (1) JPS53143348A (sv)
AU (1) AU524646B2 (sv)
BR (1) BR7803124A (sv)
CA (1) CA1136238A (sv)
CH (1) CH623412A5 (sv)
DE (1) DE2817544A1 (sv)
FR (1) FR2391451A1 (sv)
GB (1) GB1595127A (sv)
IT (1) IT1111425B (sv)
MX (1) MX149962A (sv)
NL (1) NL188541C (sv)
NO (1) NO151172C (sv)
SE (1) SE426989B (sv)
SU (1) SU759059A3 (sv)

Families Citing this family (51)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2912913C3 (de) * 1979-03-31 1982-01-07 Eduard 7303 Neuhausen Hermle Vorrichtung zur Erzeugung von Positionssignalen an Maschinen
FR2454083A1 (fr) * 1979-04-09 1980-11-07 Facom Dispositif de mesure de la position relative de deux objets
JPS5941014A (ja) * 1982-08-31 1984-03-07 Canon Inc コ−ド板
US4567410A (en) * 1984-12-03 1986-01-28 Continental Can Company, Inc. Capacitive article density monitor
GB2181610B (en) * 1985-10-08 1988-10-26 Hewlett Packard Ltd Monitoring apparatus
JPS6294251A (ja) * 1985-10-17 1987-04-30 Toshiba Mach Co Ltd 位置制御装置
JP2694827B2 (ja) * 1985-10-17 1997-12-24 東芝機械株式会社 バックラッシュ補正方法
CH665714A5 (fr) * 1985-11-22 1988-05-31 Hans Ulrich Meyer Dispositif de mesure capacitif de longueurs et d'angles.
US4786891A (en) * 1986-04-08 1988-11-22 Yokogawa Electric Corporation Absolute encoder for linear or angular position measurements
US4794393A (en) * 1986-08-22 1988-12-27 Imran Mir A Device for measuring parameters on electrocardiogram strip recordings
SE460928B (sv) * 1986-10-13 1989-12-04 Johansson Ab C E Absolutmaetande skalsystem
US4893077A (en) * 1987-05-28 1990-01-09 Auchterlonie Richard C Absolute position sensor having multi-layer windings of different pitches providing respective indications of phase proportional to displacement
US4893078A (en) * 1987-05-28 1990-01-09 Auchterlonie Richard C Absolute position sensing using sets of windings of different pitches providing respective indications of phase proportional to displacement
DE3834200A1 (de) * 1988-10-07 1990-04-12 Rexroth Mannesmann Gmbh Kapazitiver wegaufnehmer
DE69003493T2 (de) * 1989-06-29 1994-01-20 Mitutoyo Corp Kapazitive Einrichtung zur absoluten Positionsmessung.
EP0565583B1 (en) * 1991-01-04 1997-04-09 Scientific Generics Limited Remotely readable data storage devices and apparatus
US5115195A (en) * 1991-01-22 1992-05-19 Mts Systems Corporation System and method for measuring the absolute position of one body which is constrained to move with respect to another body
DE4124160C2 (de) * 1991-07-20 1994-07-28 Diehl Gmbh & Co Kapazitiver Drehwinkelgeber
DE4308462A1 (de) * 1993-03-17 1994-09-22 Vdo Schindling Anordnung zur Signalverarbeitung für Absolutwertsensoren mit periodischen Strukturen, insbesondere für Positions- und Winkelsensoren
US5477621A (en) * 1993-04-26 1995-12-26 Mitutoyo Corporation Electrical capacitance instrument and manufacturing method of the same
EP0760087B9 (en) * 1994-05-14 2005-01-05 Synaptics (UK) Limited Position encoder
US6249234B1 (en) 1994-05-14 2001-06-19 Absolute Sensors Limited Position detector
US20030062889A1 (en) * 1996-12-12 2003-04-03 Synaptics (Uk) Limited Position detector
JP3222018B2 (ja) * 1994-09-28 2001-10-22 キヤノン株式会社 光学機器
US6788221B1 (en) 1996-06-28 2004-09-07 Synaptics (Uk) Limited Signal processing apparatus and method
US6705511B1 (en) 1997-05-28 2004-03-16 Synaptics (Uk) Limited Transducer and method of manufacture
DE19729347A1 (de) * 1997-07-09 1999-01-14 Franz Gleixner Kapazitive Meßvorrichtung für Winkel oder Wege
GB9720954D0 (en) 1997-10-02 1997-12-03 Scient Generics Ltd Commutators for motors
GB9721891D0 (en) 1997-10-15 1997-12-17 Scient Generics Ltd Symmetrically connected spiral transducer
GB9811151D0 (en) 1998-05-22 1998-07-22 Scient Generics Ltd Rotary encoder
MXPA01005267A (es) * 1998-11-27 2002-04-24 Synaptics Uk Ltd Sensor de posicion.
US7019672B2 (en) * 1998-12-24 2006-03-28 Synaptics (Uk) Limited Position sensor
EP1151248B1 (de) 1999-02-05 2004-04-14 HORST SIEDLE GmbH & Co. KG. Weg- und/oder winkelaufnehmer mit mäanderförmiger messwicklung
DE19905847C2 (de) * 1999-02-05 2001-02-22 Siedle Horst Gmbh & Co Kg Weg- und/oder Winkelaufnehmer mit mäanderförmiger Meßwicklung
AU2195101A (en) * 1999-12-10 2001-06-18 Gentech Investment Group Ag Man-machine interface
US6694636B1 (en) 2000-09-01 2004-02-24 Kevin Maher Electrocardiogram compass
WO2002103622A2 (en) * 2001-05-21 2002-12-27 Synaptics (Uk) Limited Position sensor
GB2403017A (en) * 2002-03-05 2004-12-22 Synaptics Position sensor
AU2003232360A1 (en) * 2002-06-05 2003-12-22 Synaptics (Uk) Limited Signal transfer method and apparatus
GB0317370D0 (en) * 2003-07-24 2003-08-27 Synaptics Uk Ltd Magnetic calibration array
GB0319945D0 (en) * 2003-08-26 2003-09-24 Synaptics Uk Ltd Inductive sensing system
EP2145158B1 (en) 2007-05-10 2018-03-07 Cambridge Integrated Circuits Limited Transducer
US20100123302A1 (en) * 2008-11-18 2010-05-20 Ford Global Technologies, Llc Inductive vehicle seat position sensor assembly
US9727175B2 (en) 2010-05-14 2017-08-08 Elo Touch Solutions, Inc. System and method for detecting locations of touches on a projected capacitive touch sensor
JP2013526746A (ja) * 2010-05-14 2013-06-24 イーロ・タッチ・ソリューションズ・インコーポレイテッド タッチセンサ上のタッチの位置を検出するためのシステム及び方法
GB2488389C (en) 2010-12-24 2018-08-22 Cambridge Integrated Circuits Ltd Position sensing transducer
GB2503006B (en) 2012-06-13 2017-08-09 Cambridge Integrated Circuits Ltd Position sensing transducer
CN104515464A (zh) * 2013-10-03 2015-04-15 上海球栅测量系统有限公司 一种位移测量系统和装置
CN104515463A (zh) * 2013-10-03 2015-04-15 上海雷尼威尔技术有限公司 一种位移测量系统和装置
DE102020111817A1 (de) * 2020-04-30 2021-11-04 Pleiger Maschinenbau Gmbh & Co. Kg Vorrichtung zur Stellungserfassung bei hydraulischen oder elektrohydraulischen Antrieben sowie Antrieb mit Stellungserfassungsmittel
CN113884702B (zh) * 2021-10-18 2023-09-26 兰州空间技术物理研究所 一种提高静电悬浮加速度计标度因数一致性的设计方法

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2976528A (en) * 1958-11-03 1961-03-21 United Aircraft Corp Multiphase analog to digital converter
DE1221672B (de) * 1960-06-18 1966-07-28 Zuse K G Analog-Digitalwandler mit einer die Winkelstellung einer Achse od. dgl. angebenden, codierte Skalenwerte tragenden Skaleneinrichtung
US3238523A (en) * 1962-02-21 1966-03-01 Gen Precision Inc Capacitive encoder
US3286252A (en) * 1963-11-15 1966-11-15 Gen Precision Inc Capacity encoder
DE1548848A1 (de) * 1966-06-18 1970-04-09 Dresden Feinmess Zweistufige digitale Wegmesseinrichtung
US3522568A (en) * 1969-03-13 1970-08-04 Inductosyn Corp Tape scale for position measuring transformer
US3593115A (en) * 1969-06-30 1971-07-13 Ibm Capacitive voltage divider
GB1284641A (en) * 1970-01-08 1972-08-09 Ferranti Ltd Improvements relating to measuring apparatus
FR2086854A5 (sv) * 1970-04-10 1971-12-31 Commissariat Energie Atomique
US3784897A (en) * 1972-02-17 1974-01-08 Landis Tool Co Capacitor transducer
GB1386117A (en) * 1972-04-17 1975-03-05 Zeiss Jena Veb Carl Capacitive length and angle measuring device
US3961318A (en) * 1975-01-17 1976-06-01 Inductosyn Corporation Electrostatic position-measuring transducer

Also Published As

Publication number Publication date
US4504832A (en) 1985-03-12
NO151172C (no) 1985-02-20
DE2817544C2 (sv) 1989-08-17
FR2391451A1 (fr) 1978-12-15
SU759059A3 (ru) 1980-08-23
SE7805231L (sv) 1978-11-19
NL188541C (nl) 1992-07-16
NO781717L (no) 1978-11-21
NL7805353A (nl) 1978-11-21
AU3606978A (en) 1979-11-15
MX149962A (es) 1984-02-21
AU524646B2 (en) 1982-09-30
CH623412A5 (en) 1981-05-29
CA1136238A (en) 1982-11-23
NL188541B (nl) 1992-02-17
FR2391451B1 (sv) 1983-08-26
GB1595127A (en) 1981-08-05
BR7803124A (pt) 1979-02-20
SE426989B (sv) 1983-02-21
NO151172B (no) 1984-11-12
JPS53143348A (en) 1978-12-13
DE2817544A1 (de) 1978-11-23

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